Canada’s Yukon Territory announced on Tuesday that it has opened one of the largest unbroken wilderness areas in North America to mining and mineral exploration.

The government’s decree stunned indigenous leaders, who support a 2011 plan developed under Yukon land claims treaties that would have maintained the wilderness character of 80 percent of the area, which is known as the Peel watershed region. The government’s new plan all but reverses that figure, opening some 71 percent of the watershed to mining.

The Yukon features some of Canada’s highest peaks and largest glaciers, as well as tremendous expanses of lake-dotted tundra, boreal forests, and wetlands. (See “Yukon: Canada’s Wild West” in the February issue of National Geographic magazine.) It’s also rich in wildlife, with extreme seasonal shifts that beckon vast herds of caribou and other animals into motion. Larger than California but with only 37,000 inhabitants, the territory has been mostly empty of humans since the Klondike Stampede ended in the 1890s.

In recent years a new gold rush has brought a spike in population and prosperity to towns like Whitehorse and Dawson. But the rush to exploit the Yukon’s minerals—which also include zinc, copper, iron, and uranium—has unearthed growing tensions between government and mining interests on the one hand, and conservation and indigenous First Nations interests on the other.

Peel Compromise of 2011

Among the territory’s wildest quarters is the Peel watershed, a pristine, almost completely roadless wilderness that drains an area larger than Scotland.

“The Peel watershed is one of the few places left where you still have large, intact predator-prey ecosystems,” says Karen Baltgailis of the Yukon Conservation Society. “From wolves and grizzlies and eagles on down, it’s a wildlife habitat of global importance.”

The Yukon’s Peel First Nations have signed land claims agreements with the territorial and federal governments. The agreements, which lay out the procedure for land use planning, are embedded in Canada’s constitution. “We spent seven years on a well-formed and democratic public planning process,” says David Loeks, Peel Watershed Planning Commission chair.